A. Field of the Invention
The present invention relates to a feed for a layer, and more particularly to a feed for a layer which prevents the decline in eggshell quality which occurs when only vegetable feed is fed to a layer without being blended with any animal feed.
B. Description of the Related Art
There has been extensively used a feed for a layer which comprises animal feeds having a high metabolic energy such as fish meal, meat and bone meal and the like as the main component from the aspects of the economy and securing acceptable eggshell strength. Recently, there has been increased fear regarding the safety of animal feed with the possibility of an increase in food poisoning by Salmonella which gets into the inside of eggs due to the decline in the quality of the animal protein raw material and due to unsanitary treatment during its processing step, and correspondingly consumption of value added eggs has been expanded. Under these circumstances, there is a high tendency to shift the feed for a layer to a complete vegetable feed which contains no animal protein raw material. However, feeding of vegetable feed alone to a layer causes the deterioration (decline) in the eggshell quality of the produced eggs and causes a relative decrease in the number of eggs having a sufficient eggshell strength so that they stand up to handling including the selection of the eggs depending on size by machinery and transportation (delivery). The deterioration in eggshell quality leads to an increase in egg breakage rate and to selling of inexpensive liquid egg, thus giving an economical loss to layer feeding farmers. It also causes an increase in black spots appearing on the surface of the eggshell (so-called "shell mottling") which decreases the value of the eggs.